Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KPHI 261932 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 332 PM EDT SUN OCT 26 2014 .SYNOPSIS...
-- Changed Discussion --
A HIGH PRESSURE SYSTEM IN THE OHIO VALLEY WILL RIDGE INTO THE AREA TONIGHT AND MONDAY AND MOVE OFFSHORE MONDAY NIGHT. A WARM FRONT IS WILL PASS THROUGH THE AREA TUESDAY FOLLOWED BY THE PASSAGE OF A COLD FRONT ON WEDNESDAY. ANOTHER HIGH PRESSURE RETURNS INTO THE REGION ON THURSDAY AND EARLY FRIDAY. A COLD FRONT IS EXPECTED TO MOVE THROUGH THE NORTHEAST ON FRIDAY. A CANADIAN HIGH PRESSURE SHOULD BUILD INTO THE EASTERN UNITED STATES NEXT WEEKEND.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
-- Changed Discussion --
THE STRONG NORTHWESTERLY FLOW WILL GRADUALLY WEAKEN DURING THE EVENING HOURS AS THE PRESSURE GRADIENT OVER THE REGION BEGINS TO RELAX, AND AS DAYTIME MIXING COMES TO AN END AFTER SUNSET. SKIES WILL REMAIN MOSTLY CLEAR AS CLOUDS JUST TO OUR NORTH MOVE EAST AND SFC HIGH PRESSURE FROM THE OHIO VALLEY BUILDS OVER THE EASTERN SEABOARD OVERNIGHT. PATCHY FROST IS POSSIBLE NORTH OF THE MASON-DIXON LINE...BUT SINCE WE/VE ALREADY EXPERIENCED FREEZING TEMPERATURES IN THIS AREA ON OCT 20TH, THE GROWING SEASON IS OVER AND SO NO FROST ADVISORIES HAVE BEEN POSTED. LOW TEMPERATURES ARE EXPECTED TO RANGE FROM THE LOW TO MID 30S NORTH TO LOW 40S SOUTH.
-- End Changed Discussion --
&& .SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
-- Changed Discussion --
WE SHOULD START TO SFC HIGH PRESSURE CRESTS OVER THE REGION MONDAY MORNING BEFORE SLIDING OFF THE VA/NC COAST MONDAY AFTERNOON. LIGHT AND VARIABLE WINDS WILL GRADUALLY BECOME SOUTHERLY BY THE END OF THE DAY. A PLEASANT LATE OCTOBER DAY IS ON TAP, WITH HIGH TEMPERATURES A FEW DEGREES ABOVE NORMAL FOR THIS TIME OF YEAR.
-- End Changed Discussion --
&& .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
-- Changed Discussion --
THE LONG TERM STARTS UNSEASONABLY WARM AND ENDS UNSEASONABLY COOL. AT THE START OF THE LONG TERM THERE REMAINS DECENT CONSENSUS ABOUT SHOWERS OCCURRING MAINLY DURING THE DAYTIME ON WEDNESDAY (OR OUR HIGHEST CHANCES THEN) WITH A RETURN OF NEAR NORMAL TEMPS FOLLOWING. THE TRANSITION TO COOLER WEATHER AT THE END OF THE LONG TERM AS NOTED BY THE MID SHIFT REMAINS VOLATILE AS DIFFERING MODELING SOLUTIONS ARE OR ARE NOT PHASING STREAMS. THE ONE CONSENSUS THAT THE MEDIUM RANGE MODELS ARE NOW GRAVITATING TOWARD IS A NORTHERN STREAM DOMINATED SYSTEM WITH LESS IF ANY SOUTHERN STREAM INVOLVEMENT. THE MOST ROBUST OPERATIONAL RUNS HAVE NOT BEEN CLOSE TO THEIR RESPECTIVE ENSEMBLE MEAN, NOT YESTERDAY`S 12Z ECMWF RUN NOR TODAY`S GFS 12Z RUN. LOOKING AT THE BIG PICTURE AND PATTERN, THE PREDICTED TELECONNECTIVE SWITCH IS RATHER MODEST AND AS PREVIOUSLY NOTED THE FLOW LOOKS PROGRESSIVE. FAMOUS LAST WORDS, BUT THIS WOULD FAVOR SHYING AWAY FROM THE MOST ROBUST MODELING SOLUTIONS, WHICH WE CONTINUED. THERE MAY SOME WAA/RETURN FLOW HIGH CLOUDS ON MONDAY NIGHT, BUT WITH LITTLE DPVA PREDICTED OVERNIGHT WE ARE OPTING THIS WILL NOT PREVENT OUTLYING AREAS FROM RADIATING. WINDS ALOFT ARE INCREASING AS THE NIGHT PROGRESSES., WE ARE THINKING THE CALMER START WILL DEVELOP THE INVERSION THAT WILL RESIST THIS. UPSHOT WE ARE GOING WITH OR BELOW STAT GUIDANCE FOR MIN TEMPS. NO CHANGE IN THINKING FOR TUE WHICH WILL BE UNSEASONABLY WARM AND SUNNY. NO CHANGE ALSO IN THE DIFFERENCE BETWEEN SOUNDING FULL SUN MACROS (UPPER 70S TO MID 80S) AND STAT GUIDANCE MAX TEMPS (MID 60S TO LOWER 70S). BARRING SOME UNEXPECTED LOW CLOUD DECK ARRIVING FROM THE LOWER MID ATLANTIC, THE UPSIDE POTENTIAL OVER STAT GUIDANCE REMAINS RATHER HIGH. THE GRADIENT LOOKS TIGHT ENOUGH FOR SOME MIXING. PREDICTED 1390 1000-850MB THICKNESSES CONTINUE TO GENERATE HIGHS OF NEAR 80 IN THE CENTRAL CONUS. THUS WE WILL HAVE NO CHANGE IN CONTINUITY WITH MAX TEMPS WELL ABOVE STAT GUIDANCE. RECORD HIGHS ARE MAINLY IN THE LOWER TO MID 80S, LIKELY OUT OF REACH. THERE IS TIGHTER MODEL TIMING WITH THE SHOWERS ASSOCIATED WITH THE COLD FRONT. WHILE THUNDER APPEARS POSSIBLE TUESDAY WEST OF THE APPALACHIANS, INSTABILITY WANES OVERNIGHT FOR US. THE ENTRANCE REGION OF THE H2.5 JET REMAINS WELL POSITIONED STARTING TUESDAY NIGHT, SO WE CONTINUE THE CHANCE OF SHOWERS WEST TOWARD MORNING. TUESDAY NIGHT WE ARE OPTING TO GO AOA STAT GUIDANCE MIN TEMPS DUE TO CLOUDS AND THE SOUTHWEST WINDS. THE PREDICTED GFS SHORT WAVE ON WED LOOKS SPURIOUS. IN A BACKHANDED SENSE IT SLOWS THE PROGRESSION OF ITS CDFNT THRU OUR CWA BRINGING IT CLOSER TO A MODELING CONSENSUS TIMING. THAT SHORT WAVE ASIDE, OUR CWA REMAINS IN THE PREDICTED FAVORABLE ENTRANCE REGION OF THE 250MB JET PLUS PREDICTED DECENT MID LEVEL QVEC CONVERGENCE BY ALL THE MODELS. OUR POPS REMAIN ABOVE 12HR STAT GUIDANCE WITH TIMING OF HIGHEST POPS CLOSEST TO MODELING CONSENSUS. DIRECT OPPOSITE OF TUESDAY, BECAUSE OF CLOUDS AND SHOWERS, WE ARE MUCH MORE CONSERVATIVE WITH MAX TEMPS. NO CHANGE TO SHOWER CHANCES ON WEDNESDAY NIGHT. BOTH THE ECMWF AND GFS START HAVING THAT ANAFRONT LOOK TO THE PCPN LATER WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING AS THEY HINT AT A WAVE ON THE FRONT. THURSDAY AND THURSDAY NIGHT A RETURN OF SEASONABLE TEMPERATURES AND VERY LIGHT WINDS TO OUR CWA AS WEAK HIGH PRESSURE BUILDS ACROSS THE REGION. SOME CAA SC POSSIBLE NORTH ON THURSDAY. WE DID NOT MAKE TOO MANY CHANGES TO HALLOWEEN INTO SATURDAY WITH A CFP AND A NORTHERN STREAM LOW INTENSIFYING OVER NEW ENGLAND. WITH THIS 12Z RUN THE UKMET AND CAN GGEM ARE PLAYING THE PARTS OF THE MOST EXTREME OR BENIGN SOLUTIONS IN BOTH DIRECTIONS. THE GFS AND ECMWF ARE NOT THAT FAR APART. WHILE THE GFS IS NOT IN AGREEMENT WITH ITS GEFS MEAN, THE EC ENSEMBLE INFORMATION ARRIVES TOO LATE TO INCORPORATE INTO THE FORECAST. SLGT CHC/CHC OF SHOWERS MAINTAINED FRIDAY/HALLOWEEN AFTERNOON AND NIGHT. COLD ENOUGH FAR NORTHWEST, IF MOISTURE IS DEEP ENOUGH FOR PCPN, THAT IT WOULD SNOW. MAINLY DRY BUT VERY BLUSTERY WEEKEND WITH POSSIBLY SOME IMPROVEMENT WITH THE WINDS (PBLY NOT TEMPERATURES) ON SUNDAY. GIVEN THE LARGE SD SPREAD ON TEMPS OVER THE WEEKEND, LESS CONFIDENT THAN AVERAGE ABOUT THEM. HOWEVER, PRECEDING THE CFP ARRIVAL, HALLOWEEN DAY SHOULD HAVE NEAR SEASONABLE TEMPS.
-- End Changed Discussion --
&& .AVIATION /20Z SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TONIGHT AND MONDAY...VFR. GUSTY NORTHWEST WINDS WILL DIMINISH AFTER SUNSET...WITH SUSTAINED WINDS 10KT OR LESS FOR THE REMAINDER OF THE OVERNIGHT HOURS. WEST TO NORTHWEST WINDS AROUND 10 KT ARE EXPECTED MONDAY...BECOMING SW LATE IN THE DAY AT THE SAME SPEED. OUTLOOK... MONDAY NIGHT THROUGH TUESDAY EVENING...VFR. LATE TUESDAY NIGHT INTO WEDNESDAY EVENING...SCATTERED SHOWERS WITH A COLD FRONT. BRIEF MVFR POSSIBLE DURING SHOWERS, BUT PREDOMINATELY VFR. WEDNESDAY OVERNIGHT THROUGH THURSDAY NIGHT...VFR. FRIDAY...PREDOMINATELY VFR. IF CFP OCCURS FASTER, SOME MVFR POSSIBLE.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
TONIGHT...SCA CONDITIONS EXPECTED BUT WINDS WILL DECREASE DURING THE EVENING HOURS. SEAS IN THE 3 TO 4 FOOT RANGE WILL GRADUALLY DECREASE ONCE THE WINDS BEGIN TO SUBSIDE. MONDAY...SUB-SCA CONDITIONS EXPECTED AS HIGH PRESSURE MOVES OVER THE FORECAST WATERS. OUTLOOK... MONDAY NIGHT...WELL BELOW SMALL CRAFT ADVISORY CRITERIA. TUESDAY AND WEDNESDAY...SW FLOW STRENGTHENS TUESDAY. WINDS AND SEAS MAY APPROACH MARGINAL SCA TUESDAY NIGHT AND WEDNESDAY MORNING BUT CONFIDENCE IN THIS HAPPENING IS LOW THIS FAR OUT. WINDS BECOME NW BEHIND A COLD FRONT WEDNESDAY AFTERNOON AND WEAKEN. SEAS MAY REMAIN ELEVATED NEAR 4-5 FT THOUGH, NECESSITATING A SCA. WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...SUB SMALL CRAFT ADVISORY CONDITIONS. FRIDAY...SUB SMALL CRAFT ADVISORY CONDITIONS EXPECTED. CONFIDENCE IS LOWER DUE TO TIMING OF A CFP. A STRONG NORTHWEST FLOW IS ANTICIPATED BEHIND THIS FRONT.
-- End Changed Discussion --
&& .FIRE WEATHER...
-- Changed Discussion --
GUSTY NORTHWEST WINDS UP TO 30 MPH WILL SUBSIDE THIS EVENING AS HIGH PRESSURE BUILDS OVER THE AREA AND DAYTIME MIXING COMES TO AN END. THIS WILL RESULT IN WEATHER CONDITIONS LESS CONDUCIVE TO THE SPREAD OF WILD FIRES. WINDS GENERALLY IN THE 10 MPH RANGE ON MONDAY COUPLED WITH SLIGHTLY HIGHER RH VALUES SHOULD LESSEN FIRE WEATHER CONCERNS.
-- End Changed Discussion --
&& .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ450>455. SMALL CRAFT ADVISORY UNTIL 9 PM EDT THIS EVENING FOR ANZ430- 431. && $$ SYNOPSIS...GIGI/KLEIN NEAR TERM...MIKETTA SHORT TERM...MIKETTA LONG TERM...GIGI AVIATION...GIGI/KLEIN/MIKETTA MARINE...GIGI/KLEIN/MIKETTA FIRE WEATHER...MIKETTA

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.